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Outline • SDN Basics – Concepts – OpenFlow – Controller – OF-Config – Mininet 9/10/13 Software Defined Networking (COMS 6998-8) 1 SDN • For now: a new paradigm for network management • SDN widely accepted as “future of networking” – ~1000 engineers at latest Open Networking Summit – Commercialized, in production use (few places) • E.g., controls Google’s WAN; NTT moving to deploy – Much more acceptance in industry than in academia Building an Artifact, Not a Discipline • Other fields in “systems”: OS, DB, etc. – Teach basic principles – Are easily managed – Continue to evolve • Networking: – – – – Study of an artifact: the Internet Teach (mostly) big bag of protocols Notoriously difficult to manage Evolves very slowly • Networks are much more primitive and less understood than other computer systems What is Network Management? • Recall the two “planes” • Data plane: forwarding packets – Based on local forwarding state • Control plane: computing that forwarding state – Involves coordination with rest of system • Broad definition of “network management”: – Everything having to do with the control plane Original goals for the control plane • Basic connectivity: route packets to destination – Local state computed by routing protocols – Globally distributed algorithms • Interdomain policy: find policy-compliant paths – Done by fully distributed BGP • For long time, these were the only relevant goals! – What other goals are there in running a network? Also • • • • Isolation Access Control Traffic Engineering … Isolation • Want multiple LANs on single physical network • Packets on LAN don’t pass through routers – But routers used to impose various controls (later) • Use VLANs (virtual LANs) tags in L2 headers – Controls where broadcast packets go – Gives support for logical L2 networks – Routers connect these logical L2 networks • No universal method for setting VLAN state Access Control • Operators want to limit access to various hosts – Don’t let laptops access backend database machines • This can be imposed by routers using ACLs – ACL: Access control list • Example entry in ACL: <header template; drop> Summarizing • Network management has many goals • Achieving these goals is job of the control plane… • …which currently involves many mechanisms Control Plane Mechanisms • Many different control plane mechanisms • Designed from scratch for specific goal • Variety of implementations – Globally distributed: routing algorithms – Manual/scripted configuration: ACLs, VLANs – Centralized computation: Traffic engineering How Have We Managed To Survive? • Net. admins miraculously master this complexity – Understand all aspects of networks – Must keep numerus details in mind • This ability to master complexity is both a blessing – …and a curse! Mastering Complexity versus Extracting Simplicity • The ability to master complexity is valuable – But not the same as the ability to extract simplicity • Each has its role: – When first getting systems to work, master complexity – When making system easy to use, extract simplicity • You will never succeed in extracting simplicity – If you don’t recognize it is a different skill set than mastering complexity Mastering Complexity versus Extracting Simplicity • Networking has never made the distinction… – And therefore has never made the transition from mastering complexity to extracting simplicity • Still focused on mastering complexity – Networking “experts” are those that know all the details • Extracting simplicity lays intellectual foundations – This is why networking has weak foundation – We are still building the artifact, not the discipline Why make the transition • Complexity has increased to “unmanageable” levels • Consider datacenters: – 100,000s machines, 10,000s switches – 1000s of customers • Each with their own logical networks: ACLs, VLANs, etc • Way beyond what we can handle – Leads to brittle, ossify (harden) configurations – Probably inefficient too An Example Transition: Programming • Machine languages: no abstractions – Had to deal with low-level details – Mastering complexity was crucial • Higher-level languages: OS and other abstractions – File system, virtual memory, abstract data types, ... • Modern languages: even more abstractions – Object orientation, garbage collection,... Abstractions key to extracting simplicity “The Power of Abstraction” “Modularity based on abstraction is the way things get done” − Barbara Liskov Abstractions Interfaces Modularity What About Networking Abstractions? • Consider the data and control planes separately • Different tasks, so naturally different abstractions Abstractions for Data Plane: Layers Applications …built on… Reliable (or unreliable) transport …built on… Best-effort global packet delivery …built on… Best-effort local packet delivery …built on… Physical transfer of bits The Importance of Layering • Decomposed delivery into basic components • Independent, compatible innovation at each layer – Clean “separation of concerns” – Leaving each layer to solve a tractable problem • Responsible for the success of the Internet! – Rich ecosystem of independent innovation Finding Control Plane Abstractions How do you find abstractions? • You first decompose the problem…. • …and define abstractions for each subproblem • So what is the control plane problem? 21 Task: Compute forwarding state: • Consistent with low-level hardware/software – Which might depend on particular vendor • Based on entire network topology – Because many control decisions depend on topology • For all routers/switches in network – Every router/switch needs forwarding state current approach • Design one-off mechanisms that solve all three – A sign of how much we love complexity • No other field would deal with such a problem! • They would define abstractions for each subtask • …and so should we! Separate Concerns with Abstractions 1. Be compatible with low-level hardware/software Need an abstraction for general forwarding model 2. Make decisions based on entire network Need an abstraction for network state 1. Compute configuration of each physical device Need an abstraction that simplifies configuration Abs#1: Forwarding Abstraction • Express intent independent of implementation – Don’t want to deal with proprietary HW and SW • OpenFlow is current proposal for forwarding – Standardized interface to switch – Configuration in terms of flow entries: <header, action> • Design details concern exact nature of: – Header matching – Allowed actions Two Important Facets to OpenFlow • Switches accept external control messages – Not closed, proprietary boxes • Standardized flow entry format – So switches are interchangeable 26 Abs#2: Network State Abstraction • Abstraction: global network view – Annotated network graph provided through an API • Implementation: “Network Operating System” – Runs on servers in network (“controllers”) – Replicated for reliability • Information flows both ways – Information from routers/switches to form “view” – Configurations to routers/switches to control forwarding Network Operating System • Think of it as a centralized link-state algorithm • Switches send connectivity info to controller • Controller computes forwarding state – Some control program that uses the topology as input • Controller sends forwarding state to switches • Controller is replicated for resilience – System is only “logically centralized” 28 Network of Switches and/or Routers Traditional Control Mechanisms Distributed algorithm running between neighbors Complicated task-specific distributed algorithm Software Defined Network (SDN) routing, access control, etc. Control Program Global Network View Network OS Major Change in Paradigm • Control program: – Configuration = Function(view) • Control mechanism now program using NOS API • Not a distributed protocol, just a graph algorithm 32 Abs#3: Specification Abstraction • Control mechanism expresses desired behavior – Whether it be isolation, access control, or QoS • It should not be responsible for implementing that behavior on physical network infrastructure – Requires configuring the forwarding tables in each switch • Proposed abstraction: abstract view of network – Abstract view models only enough detail to specify goals – Will depend on task semantics Simple Example: Access Control A B Abstract Network View A Global Network View B Routing • Look at graph of network • Compute routes • Give to SDN platform, which passes on to switches 35 Access Control • Control program decides who can talk to who • Pass this information to SDN platform • Appropriate ACL flow entries are added to network – In the right places (based on the topology) 36 Software Defined Network Abstract Network View Virtualization Layer Control Program Global Network View Network OS Clean Separation of Concerns • Control program: express goals on abstract view – Driven by Operator Requirements • Virtualization Layer: abstract view global view – Driven by Specification Abstraction for particular task • NOS: global view physical switches – API: driven by Network State Abstraction – Switch interface: driven by Forwarding Abstraction 38 SDN: Layers for the Control Plane Control Program Abstract Network View Network Virtualization Global Network View Network OS Abstractions for Control Plane Expression of Intent …built on… Abstract Network View …built on… Global Network View …built on… Physical Topology Abstractions Don’t Remove Complexity • NOS, Virtualization are complicated pieces of code • SDN merely localizes the complexity: – Simplifies interface for control program (user-specific) – Pushes complexity into reusable code (SDN platform) • This is the big payoff of SDN: modularity! – The core distribution mechanisms can be reused – Control programs only deal with their specific function • Note that SDN separates control and data planes – SDN platform does control plane, switches do data plane Separation of Control/Data Plane • Today, routers implement both – They forward packets – And run the control plane software • SDN networks – Data plane implemented by switches • Switches act on local forwarding state – Control plane implemented by controllers • All forwarding state computed by SDN platform • This is a technical change, with broad implications 42 Changes • Less vendor lock-in – Can buy HW/SF from different vendors • Changes are easier – Can test components separately • HW has to forward • Can simulate controller • Can do verification on logical policy – Can change topology and policy independently – Can move from private net to cloud and back! – Greater rate of innovation Source: Nick Mckeown, Stanford AppAppAppAppAppAppAppAppAppAppApp Specialized Applications Specialized Operating System Specialized Hardware Vertically integrated Closed, proprietary Slow innovation 9/10/13 Small industry Open Interface Windows (OS) or Linux or Mac OS Open Interface Microprocessor Horizontal Open interfaces Rapid innovation Software Defined Networking (COMS 6998-8) Huge industry 44 Source: Nick Mckeown, Stanford AppAppAppAppAppAppAppAppAppAppApp Specialized Features Specialized Control Plane Open Interface Control Plane 9/10/13 Control Plane or Control Plane Open Interface Merchant Switching Chips Specialized Hardware Vertically integrated Closed, proprietary Slow innovation or Horizontal Open interfaces Rapid innovation Software Defined Networking (COMS 6998-8) 45 Source: Nick Mckeown, Stanford Routing, management, mobility management, access control, VPNs, … Feature Feature Million of lines of source code 6,000 RFCs Billions of gates Bloated OS Custom Hardware Power Hungry • Vertically integrated, complex, closed, proprietary • Networking industry with “mainframe” mind-set 9/10/13 Software Defined Networking (COMS 6998-8) 46 Source: Nick Mckeown, Stanford The network is changing Feature Feature Network OS Feature Feature OS Feature Feature Custom Hardware OS Feature Feature Custom Hardware OS Feature Custom Hardware Feature OS Feature Feature Custom Hardware OS 9/10/13 Custom Hardware Software Defined Networking (COMS 6998-8) 47 Source: Nick Mckeown, Stanford Software Defined Network (SDN) 3. Consistent, up-to-date global network view Feature Feature 2. At least one Network OS probably many. Open- and closed-source Network OS 1. Open interface to packet forwarding Packet Forwarding Packet Forwarding Packet Forwarding Packet Forwarding Packet Forwarding 9/10/13 Software Defined Networking (COMS 6998-8) 48 Network OS Source: Nick Mckeown, Stanford Network OS: distributed system that creates a consistent, up-to-date network view – Runs on servers (controllers) in the network – Floodlight, POX, Pyretic, Nettle ONIX, Beacon, … + more Uses forwarding abstraction to: – Get state information from forwarding elements – Give control directives to forwarding elements 9/10/13 Software Defined Networking (COMS 6998-8) 49 Source: Nick Mckeown, Stanford Software Defined Network (SDN) Control Program A Control Program B Network OS Packet Forwarding Packet Forwarding Packet Forwarding Packet Forwarding Packet Forwarding 9/10/13 Software Defined Networking (COMS 6998-8) 50 Source: Nick Mckeown, Stanford Control Program Control program operates on view of network – Input: global network view (graph/database) – Output: configuration of each network device Control program is not a distributed system – Abstraction hides details of distributed state 9/10/13 Software Defined Networking (COMS 6998-8) 51 Source: Nick Mckeown, Stanford Forwarding Abstraction Purpose: Abstract away forwarding hardware Flexible – Behavior specified by control plane – Built from basic set of forwarding primitives Minimal – Streamlined for speed and low-power – Control program not vendor-specific OpenFlow is an example of such an abstraction 9/10/13 Software Defined Networking (COMS 6998-8) 52 Source: Nick Mckeown, Stanford By comparison: Programming Machine languages: no abstractions – Had to deal with low-level details Higher-level languages: OS and other abstractions – File system, virtual memory, abstract data types, ... Modern languages: even more abstractions – Object orientation, garbage collection,… 9/10/13 Software Defined Networking (COMS 6998-8) 53 Source: Nick Mckeown, Stanford Programming Analogy What if programmers had to: – Specify where each bit was stored – Explicitly deal with internal communication errors – Within a programming language with limited expressability Programmers would redefine problem by: – Defining higher level abstractions for memory – Building on reliable communication primitives – Using a more general language 9/10/13 Software Defined Networking (COMS 6998-8) 54 Source: Nick Mckeown, Stanford Specification Abstraction Network OS eases implementation Next step is to ease specification Provide abstract view of network map Control program operates on abstract view Develop means to simplify specification 9/10/13 Software Defined Networking (COMS 6998-8) 55 Source: Nick Mckeown, Stanford Software Defined Network (SDN) Abstract Network View Virtualization Control Program A Control Program B Global Network View Network OS Packet Forwarding Packet Forwarding 9/10/13 Packet Forwarding Packet Forwarding Packet Software Defined Networking (COMS 6998-8) Forwarding 56 Outline • Review of previous lecture • SDN Basics – Concepts – OpenFlow – Switches and Controllers – OF-Config – Mininet 9/10/13 Software Defined Networking (COMS 6998-8) 57 OpenFlow • Why OpenFlow? • How does OpenFlow work? 9/10/13 Software Defined Networking (COMS 6998-8) 58 Why OpenFlow? 9/10/13 Software Defined Networking (COMS 6998-8) 59 The Ossified Network Routing, management, mobility management, access control, VPNs, … Feature Feature Operating System Specialized Packet Forwarding Hardware Million of lines of source code 5400 RFCs Barrier to entry Billions of gates Bloated Power Hungry Many complex functions baked into the infrastructure OSPF, BGP, multicast, differentiated services, Traffic Engineering, NAT, firewalls, MPLS, redundant layers, … An industry with a “mainframe-mentality”, reluctant to change 9/10/13 Software Defined Networking (COMS 6998-8) 60 Research Stagnation • Lots of deployed innovation in other areas – OS: filesystems, schedulers, virtualization – DS: CDNs, MapReduce – Compilers: JITs, vectorization • Networks are largely the same as years ago – Ethernet, IP, WiFi • Rate of change of the network seems slower in comparison – Need better tools and abstractions to demonstrate and deploy 9/10/13 Software Defined Networking (COMS 6998-8) 61 Closed Systems (Vendor Hardware) • • • • Stuck with interfaces (CLI, SNMP, etc) Hard to meaningfully collaborate Vendors starting to open up, but not usefully Need a fully open system – a Linux equivalent 9/10/13 Software Defined Networking (COMS 6998-8) 62 OpenFlow: a pragmatic compromise • + Speed, scale, fidelity of vendor hardware • + Flexibility and control of software and simulation • Vendors don’t need to expose implementation • Leverages hardware inside most switches today (ACL tables) 9/10/13 Software Defined Networking (COMS 6998-8) 63 How does OpenFlow work? 9/10/13 Software Defined Networking (COMS 6998-8) 64 Ethernet Switch 9/10/13 Software Defined Networking (COMS 6998-8) 65 Control Path (Software) Data Path (Hardware) 9/10/13 Software Defined Networking (COMS 6998-8) 66 OpenFlow Controller OpenFlow Protocol (SSL/TCP) Control Path OpenFlow Data Path (Hardware) 9/10/13 Software Defined Networking (COMS 6998-8) 67 OpenFlow Example Software Layer Controller PC OpenFlow Client Flow Table Hardware Layer MAC src MAC dst IP Src IP Dst TCP TCP Action sport dport * * * 5.6.7.8 * port 1 5.6.7.8 9/10/13 port 2 * port 3 port 1 port 4 1.2.3.4 Software Defined Networking (COMS 6998-8) 68 OpenFlow Basics Flow Table Entries Rule Action Stats Packet + byte counters 1. 2. 3. 4. 5. Switch VLAN Port ID Forward packet to zero or more ports Encapsulate and forward to controller Send to normal processing pipeline Modify Fields Any extensions you add! VLAN MAC pcp src MAC dst Eth type IP Src IP Dst IP L4 IP ToS Prot sport L4 dport + mask what fields to match 9/10/13 Software Defined Networking (COMS 6998-8) 69 Examples Switching Switch MAC Port src * MAC Eth dst type 00:1f:.. * * VLAN IP ID Src IP Dst IP Prot TCP TCP Action sport dport * * * * IP Dst IP Prot TCP TCP Action sport dport * * port6 Flow Switching Switch MAC Port src MAC Eth dst type port3 00:20.. 00:1f.. 0800 VLAN IP ID Src vlan1 1.2.3.4 5.6.7.8 4 17264 80 port6 Firewall Switch MAC Port src * 9/10/13 * MAC Eth dst type * * VLAN IP ID Src IP Dst IP Prot TCP TCP Action sport dport * * * * * Software Defined Networking (COMS 6998-8) 22 drop 70 Examples Routing Switch MAC Port src * * MAC Eth dst type * * VLAN IP ID Src IP Dst * 5.6.7.8 * * VLAN IP ID Src IP Dst IP Prot vlan1 * * * TCP TCP Action sport dport port6, port7, * * port9 * IP Prot TCP TCP Action sport dport * port6 VLAN Switching Switch MAC Port src * 9/10/13 * MAC Eth dst type 00:1f.. * Software Defined Networking (COMS 6998-8) 71 Centralized vs Distributed Control Both models are possible with OpenFlow Centralized Control Controller OpenFlow Switch Distributed Control Controller OpenFlow Switch Controller OpenFlow Switch OpenFlow Switch OpenFlow Switch 9/10/13 Controller OpenFlow Switch Software Defined Networking (COMS 6998-8) 72 Flow Routing vs. Aggregation Both models are possible with OpenFlow Aggregated Flow-Based • • • • Every flow is individually set up by controller Exact-match flow entries Flow table contains one entry per flow Good for fine grain control, e.g. campus networks 9/10/13 • • • • One flow entry covers large groups of flows Wildcard flow entries Flow table contains one entry per category of flows Good for large number of flows, e.g. backbone Software Defined Networking (COMS 6998-8) 73 Reactive vs. Proactive (pre-populated) Both models are possible with OpenFlow Reactive Proactive • • • • • First packet of flow triggers controller to insert flow entries Efficient use of flow table Every flow incurs small additional flow setup time If control connection lost, switch has limited utility 9/10/13 • • • Controller pre-populates flow table in switch Zero additional flow setup time Loss of control connection does not disrupt traffic Essentially requires aggregated (wildcard) rules Software Defined Networking (COMS 6998-8) 74 Usage examples • Alice’s code: – Simple learning switch – Per Flow switching – Network access control/firewall – Static “VLANs” – Her own new routing protocol: unicast, multicast, multipath – Home network manager – Packet processor (in controller) – IPvAlice – – – – – VM migration Server Load balancing Mobility manager Power management Network monitoring and visualization – Network debugging – Network slicing … and much more you can create! 9/10/13 Software Defined Networking (COMS 6998-8) 75 Outline • Review of previous lecture • SDN Basics – Concepts – OpenFlow – Switches and Controllers – OF-Config – Mininet 9/10/13 Software Defined Networking (COMS 6998-8) 76 Switches and Controllers • OpenFlow switches and vendors • Controllers – Floodlight – Beacon – Nox/pox – …. 9/10/13 Software Defined Networking (COMS 6998-8) 77 OpenFlow building blocks oftrace oflops Monitoring/ debugging tools openseer Stanford Provided ENVI (GUI) NOX LAVI Beacon FlowVisor Console n-Casting Helios 9/10/13 Applications SNAC Controller Maestro Slicing Software FlowVisor Stanford Provided Commercial Switches HP, NEC, Pronto, Juniper.. and many more Expedient Software Ref. Switch NetFPGA Broadcom Ref. Switch OpenWRT PCEngine WiFi AP OpenVSwitch Software Defined Networking (COMS 6998-8) OpenFlow Switches 78 78 Current SDN hardware Juniper MX-series NEC IP8800 WiMax (NEC) HP Procurve 5400 Netgear 7324 PC Engines Pronto 3240/3290 Ciena Coredirector More coming soon... 9/10/13 Software Defined Networking (COMS 6998-8) 79 Commercial Switch Vendors Model Virtualize Notes HP Procurve 5400zl or 6600 1 OF instance per VLAN -LACP, VLAN and STP processing before OpenFlow -Wildcard rules or non-IP pkts processed in s/w -Header rewriting in s/w -CPU protects mgmt during loop NEC IP8800 1 OF instance per VLAN -OpenFlow takes precedence -Most actions processed in hardware -MAC header rewriting in h/w Pronto 3240 or 3290 with Pica8 or Indigo firmware 1 OF instance per switch 9/10/13 -No legacy protocols (like VLAN and STP) -Most actions processed in hardware -MAC header(COMS rewriting Software Defined Networking 6998- in h/w 8) 80 Controller Vendors Vendor Notes Vendor Notes Nicira’s NOX •Open-source GPL •C++ and Python •Researcher friendly Stanford’s Beacon •Open-source •Researcher friendly •Java-based Nicira’s ONIX •Closed-source •Datacenter networks BigSwitch controller •Ha open source version •Based on Beacon •Enterprise network SNAC •Open-source GPL •Code based on NOX0.4 •Enterprise network •C++, Python and Javascript •Currently used by campuses Maestro (from Rice Univ) •Open-source •Based on Java Frenetic or Nettle •Open-source •Written in functional programming languages 9/10/13 Software Defined Networking (COMS 6998-8) 81 Floodlight Architecture Source: Big Switch Networks Overview FloodlightProvider (IFloodlightProviderService) TopologyManager (ITopologyManagerService) LinkDiscovery (ILinkDiscoveryService) – Floodlight is a collection of modules – Some modules (not all) export services Forwarding DeviceManager (IDeviceService) StorageSource (IStorageSourceService) – All modules in Java – Rich, extensible REST API RestServer (IRestApiService) StaticFlowPusher (IStaticFlowPusherService) VirtualNetworkFilter (IVirtualNetworkFilterService) 82 Software Defined Networking (COMS 6998-8) Floodlight Architecture Source: Big Switch Networks Module descriptions FloodlightProvider (IFloodlightProviderService) Translates OF messages to Floodlight events Managing connections to switches via Netty TopologyManager (ITopologyManagerService) • • Computes shortest path using Dijsktra Keeps switch to cluster mappings LinkDiscovery (ILinkDiscoveryService) Maintains state of links in network Forwarding Installs flow mods for end-to-end routing DeviceManager (IDeviceService) Tracks hosts on the network StorageSource (IStorageSourceService) DB style storage (queries, etc) RestServer (IRestApiService) Implements via Restlets (restlet.org) StaticFlowPusher (IStaticFlowPusherService) Supports the insertion and removal of static flows VirtualNetworkFilter (IVirtualNetworkFilterService) Create layer 2 domain defined by MAC address Sends out LLDPs Handles island routing MAC -> switch,port, MAC->IP, IP->MAC Modules can access all data and subscribe to changes Modules export RestletRoutable REST-based API Used for OpenStack / Quantum 8383 Software Defined Networking (COMS 6998-8) Floodlight Programming Model Northbound APIs IFloodlightModule Java module that runs as part of Floodlight External Application Consumes services and events exported by other modules OpenFlow (ie. Packet-in) Switch add / remove Device add /remove / move REST IFloodlightModule Link discovery Floodlight Controller External Application Switch Communicates with Floodlight via REST Quantum / Virtual networks Normalized network state Static flows Software Defined Networking (COMS 6998-8) Switch vSwitch Switch 84 REST API Reference Source: Big Switch Networks A moving target…but… Network State Static Flows Virtual Network User Extensions List Hosts Add Flow Create Network … List Links Delete Flow Delete Network List Switches List Flows Add Host GetStats (DPID) RemoveAll Flows Remove Host GetCounters (OFType…) Floodlight Controller Switch Switch Switch vSwitch Software Defined Networking (COMS 6998-8) 85 Programming Floodlight Using the REST API • Fine-grained ability to push flows over REST • Access to normalized topology and device state • Extensible access to add new APIs Software Defined Networking (COMS 6998-8) 86 Programming Floodlight Source: Big Switch Networks Creating a module • Handle OpenFlow messages directly (ie. PacketIn) • Expose services to other modules • Add new REST APIs Software Defined Networking (COMS 6998-8) 87 Outline • Review of previous lecture • SDN Basics – Concepts – OpenFlow – Switches and Controllers – OF-Config – Mininet 9/10/13 Software Defined Networking (COMS 6998-8) 88 OpenFlow configuration and Management Protocol • Bootstrap OpenFlow network • Switch connects to controller • Controller(s) to connect to must be configured at switches controller controller • Allocate resources within switches • Ports • Queues • ... switch switch switch switch 89 9/10/13 Software Defined Networking (COMS 6998-8) OpenFlow configuration and Management Protocol: Reference Model • Configuration Point • Source of switch configuration • OpenFlow Capable Switch • Hosts one or more logical switches Configuration Configuration Point Point OF-CONFIG Configuration OpenFlow Point Controller using IETF Netconf & XML data models OpenFlow Capable Switch • OpenFlow Controller • OpenFlow Logical Switch • instance of an OpenFlow Switch OpenFlow OF Logical Switch resources (ports, queues) 90 9/10/13 Software Defined Networking (COMS 6998-8) Configuration OpenFlow Point Controller OpenFlow OF Logical Switch OF-CONFIG Scope and Releases • OF-CONFIG 1.0 (Jan 2012) based on OpenFlow 1.2 • assigning controllers to logical switches • retrieving assignment of resources to logical switches • configuring some properties of ports and queues WG established in Sep 2011 • OF-CONFIG 1.1 (Apr 2012) based on OpenFlow 1.3 • added controller certificates and resource type "table" • retrieving logical switch capabilities signaled to controller • configuring of tunnel endpoints • OF-CONFIG 1.1.1 (Aug 2012) based on OpenFlow 1.3.1 • consolidation of version 1.1, fixing small inconsistencies • OF-CONFIG 1.2 (early 2013) based on OpenFlow 1.3.1 • features still under discussion, candidates include • retrieving capable switch capabilities, configuring logical switch capab. • assigning resources to logical switches • simple topology detection • event notification 91 9/10/13 Software Defined Networking (COMS 6998-8) Use of Netconf and Yang • Netconf was chosen as management protocol • not necessarily accepted as ideal solution • still discussing alternatives • XML schema was chosen as modeling language • So far, the focus has been on configuration • bootstrap of an OpenFlow network is the obvious first thing to do 92 9/10/13 Software Defined Networking (COMS 6998-8) Mininet • Machine-local virtual network – great dev/testing tool • Uses linux virtual network features – Cheaper than VMs • Arbitrary topologies, nodes Mininet (Cont’d) • Rapidly prototype, develop and test – Interestingly-sized networks (16-100 nodes) start up in seconds – No lengthy lab reconfiguration or rebooting required – Always-accessible network resources, in any topology, at essentially no cost – Designs that work on Mininet transfer seamlessly to hardware for full speed operation 9/10/13 Software Defined Networking (COMS 6998-8) 94 Mininet (Cont’d) • Repeatably test, analyze, and predict network behavior – Easy replication of experimental and test results – Examine effects of code or network changes before testing/deploying on hardware – Allows automated system-level tests and experiments – Recreate real-world network and test cases for a variety of topologies and configurations 9/10/13 Software Defined Networking (COMS 6998-8) 95 Mininet (Cont’d) • Quickly get up and running – Free and permissively licensed (BSD) – Minimal hardware requirements – Accessible to novices thanks to simple CLI – Smooth learning curve thanks to walkthrough, tutorial, examples and API documentation – Strong users and support community 9/10/13 Software Defined Networking (COMS 6998-8) 96 Questions? 9/10/13 Software Defined Networking (COMS 6998-8) 97